Animal model preparation
Six adult male New Zealand rabbits weighing an average of 2-3 kg, were used in this sub-study. Each rabbit was given an overdose of pentobarbital sodium (30 mg/kg intravenously) and was anticoagulated with heparin (180 IU/kg), the chest was open and heart was quickly excised and placed in cold cardioplegic resolution([K+]0=8mM; 4℃).
PVs, SVC, right atrium (RA) and left atrium (LA) were isolated from atrium. The preparations were placed in a small tissue bath and super-fused with Tyrode’s solution. Tyrode’s solution contains: (mmol/L) NaCl 137, NaHCO3 15, KCl 4, CaCl2 2.7, MgCl2 0.5, NaH2PO4 0.5 and glucose 11 (pH 7.4). The tissue was super-fused at tissue bath with Tyrode’s solution at 5ml/minute rate and 37℃.